摘要：
A light transmissive structure includes a light transmissive substrate having first and second opposing faces, and an array of microprism elements on the first face. Each microprism element includes a first inclined surface disposed at a first inclined angle relative to the second face, and a second inclined surface disposed at a second inclined angle relative to the second face. The first inclined angle is less than the second inclined angle, and a peak angle between the first inclined surface and second inclined surface is in the range of about 70 degrees to about 100 degrees. The second inclined surface has a convex curvature when viewed from angles perpendicular thereto. The light transmissive structure is configured to receive light from a light source facing the first face in a first direction and redistribute light emerging from the second face in a second direction different from the first direction.
权利要求：
1. A light transmissive structure (30) comprising: a light transmissive substrate (32) having first and second opposing faces (34, 36); and an array (50, 60, 70, 80) of microprism elements (38, 52, 62, 72, 82) on the first face, each microprism element comprising a first inclined surface (54, 64, 74, 84) disposed at a first inclined angle (55, 65, 75, 85) relative to the second face, and a second inclined surface (56, 66, 76, 86) disposed at a second inclined angle (57, 67, 77, 87) relative to the second face, the first inclined angle being less than the second inclined angle, a peak angle (59, 69, 79, 89) between the first inclined surface and second inclined surface being in the range of about 70 degrees to about 100 degrees, the second inclined surface having a convex curvature when viewed from angles perpendicular thereto, wherein the microprism elements are arrayed on the light transmissive substrate in a grid along perpendicular rows and columns so that the light transmissive structure is configured to receive light emitted from a light source (20) facing the first face, the light having a luminous intensity distribution centered in a first direction and, in response, to emit redistributed light from the second face, the redistributed light having a luminous intensity distribution centered in a second direction different from the first direction.
2. The light transmissive structure according to claim 1, wherein the redistributed light emitted from the second face (36) has an asymmetric distribution.
3. The light transmissive structure according to any of claims 1 and 2, wherein the first inclined angle (65) is in the range of about 10 degrees to about 40 degrees.
4. The light transmissive structure according to any of claims 1-3, wherein the second inclined angle (67) is in the range of about 40 degrees to about 100 degrees.
5. The light transmissive structure according to any of claims 1-4, wherein each of the microprism elements (62) has a length of about 100 µm and a width of about 40 µm.
6. The light transmissive structure according to any of claims 1-5, wherein the microprism elements (62) alternate position by one-half a period in each row.
7. The light transmissive structure according to any of claims 1-6, wherein the first inclined surface (64) is substantially planar.
8. The light transmissive structure according to claim 1, further comprising a rippled pattern (78) across the array (70) of microprism elements (72), the rippled pattern having a plurality of peaks (78a) and a plurality of valleys (78b).
9. The light transmissive structure according to claim 8, wherein the rippled pattern (78) has 20 µm period in a third direction (y) and a 60 µm period in a fourth direction (x) orthogonal to the third direction.
10. The light transmissive structure according to claim 1, wherein at least some of the microprism elements (82) are curved and nested.
11. The light transmissive structure according to claim 10, wherein the nested and curved microprism elements (82) approximately fill a hexagonal shape (83).
12. The light transmissive structure according to claim 11, wherein the hexagonal shape (83) is approximately 270 µm in size.
13. The light transmissive structure according to claim 11, wherein the light transmissive structure comprises a plurality of hexagonal shapes (83) comprising the curved and nested microprism elements (82).
14. A lighting system (10) comprising: a light source (20); and a light transmissive structure (30) according to any of claims 1-13.